Vehicular traffic approaching a junction, such as an intersection or a split at which an entrance ramp or an exit ramp merge with a highway or the like, may frequently have a wide variety of speeds. With respect to a roadway having multiple lanes that approaches an intersection, the vehicles traveling along the center lane(s) that proceed directly through the intersection generally have a relatively high speed, while vehicles traveling in the rightmost lane that make a right turn at the intersection may have an intermediate speed and vehicles traveling in the leftmost lane that make a left turn at the intersection may have a relatively slower speed. Thus, the distribution of vehicular speeds along the roadway approaching a junction may be multi-modal with multiple clusters of vehicular speeds. With respect to the foregoing example of traffic approaching an intersection along a multi-lane roadway, there may be a first cluster of relatively high vehicular speeds, a second cluster of intermediate vehicular speeds and a third cluster of relatively slow vehicular speeds.
For purposes of routing and navigation, vehicular speeds along the link of a roadway that approaches a junction are generally averaged with the resulting average speed then being utilized for route planning including the identification of the fastest route and for the determination of an estimated time of arrival. Because of the sometimes significant differences in the speed of vehicles approaching a junction as exemplified by the multi-modal distribution of vehicular speeds, reliance upon an average speed may produce less accurate results in terms of routing and navigation than may be desired. For example, the utilization of an average speed from a multi-modal distribution of vehicular speeds along the link of a roadway approaching a junction may result in the generation of inaccurate traffic information for the link, thereby potentially leading to an indication that falsely indicates that a link is congested or a failure to detect congestion.
Although the multi-modal distribution of vehicular speeds along a link of a roadway approaching a junction may be attributable to the different speeds that the vehicles are able to travel in the different lanes of the link, current techniques for identifying the position of the vehicle during travel along the roadway are unable to consistently identify the particular lane in which the vehicle is located and, instead, simply identifies the link of the roadway along which the vehicle is traveling. Thus, the vehicle and, in turn, the speed of a vehicle traveling along the link of a roadway approaching a junction is associated with the link in general and not with a respective lane of the link. As such, routing and navigation systems are unable to discriminate between the expected travel time for vehicles driving in the different lanes of a link of a roadway approaching a junction and, as such, analyze the speed of the vehicles traveling along the link of the roadway approaching a junction in the aggregate which, in turn, leads to inaccurate traffic information in some instances.